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Friday, March 8, 2013

KEF LS50 Loudspeaker Review

Fifty years may not seem like a long time, but for a loudspeaker manufacturer in 2013 it is an eternity. How many electronics manufacturers can you name off the top of your head who have been around for five decades? Sony. Yamaha. Marantz. JBL. There are certainly others but for a loudspeaker manufacturer that is quite the milestone. KEF, based in the United Kingdom (although it is now owned by Hong Kong-based Gold Peak Group), was founded in 1961 by Raymond Cooke and named after Kent Engineering and Foundry which formerly occupied the site of its factory in Maidstone.

KEF at 50 wasn't a year where the manufactuer merely patted itself on the back and said "Nicely done, lads, here's to the next 50," but a relaunching of the brand with a series of new products that had members of the press drooling and the competition scratching its head and sweating in sheer panic. Be afraid. Be very afraid. The Blade loudspeakers which will run you a paltry $30,000 are the culmination of years of driver development and the success that is KEF's Uni-Q design. The Blade is not the most expensive loudspeaker that KEF manufactures (Muon - $198,000 pair) but what is clear is that the millions of dollars that KEF invested in their top two models has trickled down into the rest of their product line-up including the LS50 50th Anniversary monitors which retail for $1,500 a pair.

Not to give the rest of the story away so quickly, but the LS50 may be one of the best loudspeakers I've ever heard (and I hear a lot); which is utterly amazing considering their asking price.

We can't remember a product in recent years that has caused such a stir; primarily because it offers so much for such a reasonable asking price. Yes, $1,500 for these loudspeakers is KEF being utterly generous.

From a home theater perspective, the LS50s are probably not as practical as KEF's R-series; which also utilizes KEF's Uni-Q technology, because the LS50 is only sold in pairs [editor's note: KEF reps tell us that you actually can order a single LS50. Contact your local authorized KEF dealer for details]. Also, you may want a larger center channel loudspeaker to anchor your home theater system. KEF's R200c ($1,000) is pretty close from a tonal perspective but not inexpensive. The R600c ($1500), however, is an excellent match and one of the best center channels we've heard from any manufacturer at any price so it may be something to think about if you can swing around $6,000 for an entire 5.1 set-up.

But back to the subject at hand, as fantastic as the LS50s are with music, they were clearly designed with two-channel audio in mind; as nearfield monitors on a desktop or on stands in your den or media room.

So what's in the little black box with the rose gold Uni-Q driver?

The LS50s are a two-way bass reflex monitor that utilize KEF's revolutionary Uni-Q driver; a 1" vented aluminium dome tweeter and a 5.25" midrange/low frequency driver made from an aluminium/magnesium alloy. The Uni-Q driver on the LS50 utilizes the 5.25" woofer than can be found in KEF's R-series but the 1" tweeter is derived from the more expensive Blade and is combined with a neodymium magnet, that KEF has mounted on the woofer motor's central pole-piece.

The benefit of the Uni-Q driver is that the entire sound -- all of the frequencies, from bass to treble -- emanates from one source, resulting in a more precise image that is also quite large. The LS50s can reproduce scale with ease and the improvements in coherency are quite noticeable.

The LS50s quoted frequency response is 79Hz - 28kHz +/- 3dB and the 85dB sensitivity rating means that you need a decent amplifier to drive these, but as our tests prove, you don't need a $5,000 amplifier to make these loudspeakers sing. The LS50s are rated at 8 ohms but they do dip to between 4-5 ohms once you crossover 200Hz and into the higher frequency bands. Any amplifier that can present a stable load into 4 ohms will do just fine.

The rear-port is also rather interesting. Stick your finger inside (pervert) and you'll discover that KEF has rather creatively used closed-cell foam. The material and design help to reduce colorations in the port. The cabinet itself is very well braced and manufactured from a combination of MDF, high-density foam, and a high gloss piano black cabinet.

A pair of high-quality binding posts finishes off the design which does not come with speaker grilles. You get to stare at that gorgeous rose gold Uni-Q driver 24-7.

Before we get into how these sound, we want to address the issue of set-up and how to get the most out of them should you decide to pull the trigger.

The LS50s are rear-ported monitors, so you will want to give them some space from the wall behind them. Push them too close to the wall and bass loses some of its definition. You may gain some weight down below but you'll be sacrificing detail and these loudspeakers excel in that regard.

The LS50s are certainly larger than most monitors; 11.9"H x 7.9"W x 10.9"D and are deceptively heavy at 16 pounds each.

While you can get away with placing the LS50s on a credenza or media console (nothing higher than 26" based on our experimentation), they really need to be set-up on proper stands. Big, ugly, metal stands filled with sand or shot. 24"-26" stands is the highest you should go and we would suggest avoiding single-post stands unless the main tube is really wide and the top plate can hold the entire bottom surface of the cabinet.

Depending on your height sitting in your listening chair or on the sofa, a 24" stand places the tweeter at about 31" from the floor. If you are on the tall side (as I am at 6' 3"), that may force you to slouch in the seat to achieve the best balance. My media room chair is rather low to compensate for my height so I am able to get away with 24" stands. Just something to think about.

So where does that leave you?

If you can swing it, the 24" 3-post/4-post stands from Sound Anchors are the best option I've used, but be prepared to spend upwards of...wait for it...$700.00 for a set of stands. I've owned a pair of the 4-post stands for 7 years and nothing comes close.

Cheaper options?

Atacama, Partington, and Apollo are all really good options that are popular in the U.K. and are a lot cheaper than the U.S. manufactured Sound Anchor stands. If you can find a pair of Target HR stands, expect to spend at least $350.00 for a pair.

The LS50 sound best if you can place them at least 2 feet from the wall behind them and 2-3 feet from the sidewalls. Give them space to breathe and you will be amazingly impressed at their imaging capabilities and bass response.

In terms of cabling and amplification, the LS50 will surprise you with their versatility and ability to play with others. When thinking about loudspeaker cables with the LS50s, stick with copper-based offerings from AudioQuest, Analysis Plus, Nirvana, Kimber, Cardas, or Auditorium 23. The LS50 have tremendous resolution and midrange prowess that few $10,000 loudspeakers even hint at (seriously) so it would not be a mistake to splurge a little when it comes to cables with these loudspeakers.

The Analysis Plus Black Oval 12 and 9 loudspeaker cables should run you between $240.00 - $455.00 for an 8-foot pair with banana pins and you would be hard pressed to justify spending more. The Auditorium 23 loudspeaker cables from Germany were a close second to the Analysis Plus Black Oval 9 in my admittedly unscientific listening tests, but they will run an additional $500-600 depending on length. The real surprise were the AudioQuest X2 bulk cables that you can pick-up for around $4/foot at Best Buy. Whle not as revealing as the more expensive cables from Michigan and Schwalbach, the flat inexpensive cables from AQ make a serious case for themselves if you are looking to run long runs of cable and wire up an entire home theater.

As good as the LS50s are with $4/foot loudspeaker cables, they are even better with inexpensive amplification; however, that's not to say that don't sound better with expensive amplifiers. They most certainly do. For this review, we decided to drag out everything at our disposal and even auditioned the LS50s at another location which gave us access to a Bel Canto REF500S ($2,500) stereo Class D amplifier which can output a healthy 250 watts per channel into 8 ohms and a Parasound Halo A23 amplifier.

At the bottom end, I drove the LS50s with a Denon AVR-591 receiver ($400), Rega Brio-R integrated amplifier ($895) and an Anthem MRX-500 AV receiver which retails for slightly under $1,500.

The $400 Denon didn't humiliate itself at all which told me a few things about the LS50; it's easy to drive, it sounds excellent with a wide range of products, and you don't need to go crazy and spend $5,000 on an amplifier to get great sound out of them.

Unless you lean toward overly clinical solid state amplification, with sharp ultra-defined high frequencies, you won't be disappointed. My personal favorite, based on listening, was the $895 Rega Brio-R which is a perfect match for the LS50s; rich and detailed sounding midrange and top end, dynamic, taut bass, and soundstage depth to die for.

KEF likes to demonstrate the LS50s at trade shows with the entry-level Parasound Halo amplifiers so we arranged to hear the combination and it was highly resolving, airy, and capable of handling all types of music or films at really loud listening levels.

So what's all the hubbub...bub?

If the KEF LS50s were $7,500, I would say that they were overpriced but that their sound quality certainly matches some products in that price range that I've heard over the years; Dynaudio Focus 340s, DeVore Fidelity Nines, and the Sonus Faber Cremona M. No, I'm not kidding. That KEF has wrung this level of resolution and coherency out of a pair of $1,500 monitors is remarkable.

Are there better speakers than the LS50s under $5,000? There are certainly a number of loudspeakers that I enjoy listening to from Harbeth, Spendor, Magnepan, and Paradigm, but truth be told, I would rather own the LS50s, drive them with either the Rega Brio-R or Anthem MRX-500, spend more on a good source and USB DAC, and go to bed at night knowing that I spent my money wisely.

The KEFs are a well-balanced sounding design that do a lot of the little things really well; imaging, detail, and microdynamics. Their bass response is deep, taut, and very quick for such a small driver. They can fill a large room with highly resolved sound so metal and large symphonic works are in order, but they also excel with vocals, chamber music, jazz, and blues.

Do they need a subwoofer?

If you plan on using 2 pairs of LS50s with a KEF R200c center channel speaker in a home theater, I would advise adding a subwoofer such as the KEF R400b or a REL R-218. Both integrate well with the LS50s and are good for both music and movies.

If you plan on using the LS50s for music only, they're perfectly fine unaccompanied if the room is small-medium sized. If the room is larger than 20 x 13 x 9 feet, I would add one of the aforementioned subwoofers and let the it handle everything below 80Hz. If you plan on watching films as well, the subwoofer would make sense giving you a really potent 2.1 system that would keep you entertained for years.

Watching Skyfall through the LS50s matched with the REL R-218 was quite an experience. The stereo presentation was not as immersive as a 5.1 set-up but it gave up very little when it came to dynamics, midrange punch, or LFE content. Adele's Oscar-winning theme set the stage for one of the best Bond opening chase sequences and we were hooked from the first note.

Switching over to music, the KEFs really excel with reproducing the human voice; Adele, Richard Thompson, Nick Cave, Sam Cooke, and Nina Simone had a gestalt that few loudspeakers are able to recreate. The LS50s reproduced each one differently, adding just enough warmth and detail to make it that much more palpable.

Did the KEFs ever stumble?

With the Denon AVR-591, I heard a hardness in the treble that could become irritating over time, but as I listened to more and more products, I realized that the LS50's capabilities are only limited by your choice of amplifier and source. For a $1,500 loudspeaker, that's rather remarkable. The LS50s will work well with a large number of products and that versatility makes them likely to find homes in many systems much to the chagrin of the competition.

Turn-Ons:

One of the best sounding loudspeakers you can buyAbsurdly inexpensive considering its performanceGorgeous design and build qualityWorks well with both music and moviesEasy to set-up and positionCan be driven by a 50 W/channel amplifier and sound greatState-of-the-art technology Can't purchase just one for a center channelWill make you want to upgrade every other component to hear what they are capable ofNeed good ("expensive") stands for best results Require a subwoofer for home theater if you plan on a 5-channel or 7-channel set-upIt's not very often that a $1,500 pair of loudspeakers shakes up an entire product category and can hold its own against products that are four times the price, but the KEF LS50 does just that. Solid engineering, gorgeous design, and excellent sound quality make this the speaker to own for both music and home theater use. The LS50s are a wake-up call; a stampeding elephant that should have other manufacturers thinking about how to deliver more for less. A product that was long overdue and hopefully a catalyst for those looking to invest in a real high-end loudspeaker without requiring a mortgage or third job. Our highest possible recommendation. Bravo KEF.Product Details and